'We need to have a serious talk,' he said Wednesday in an interview in Stockholm. 'We need to calibrate, we cannot just add on. I think it is going beyond reason.'

Bankers across Europe are trying to anticipate what regulatory changes might follow the results of stress tests by the European Central Bank and the European Banking Authority, with results due to be released on Oct. 26. The examinations will establish the financial health of Europe’s biggest banks and provide a master document from which the ECB can start its supervisory work on Nov. 4.